92 COMPANION TO TROPICAL READERS 



103. Proportion of organic matter in soils. 



104. Leaves become decomposed and form humus. 



105. Humus becomes darker in colour when wet. 



106. Pure sand contains no plant food. 



107. Different kinds of soil. 



Tillage. 



112. Value of tillage. 



113. Roots develop more extensively in a well-tilled 

 soil. 



114. Water is more readily absorbed in a well-tilled 

 soil. 



115. A loose surface aids in retaining water in the 

 soil. 



116. Methods of tillage. 



Drainage. 



118. Drainage a necessity. 



119. Water is found below the surface of the soil. 



120. To detect whether drainage is necessary. 

 122. Lime as an aid to free drainage. 



How we rob the Soil. 



1 24. Soils become exhausted when continually cropped. 



125. One reason for practising rotation of crops. 



Insect Pests. 



144 a. Hand-picking. 



144 b. Spraying for biting insects with Paris green. 



144 c. Kerosene emulsion for sucking insects. 



II. DEVELOPMENT OF INTEREST IN GARDENING 



This is an important side of the subject, and one 

 affecting the future prosperity of the island. 



Teachers will have to exercise tact, and though the 

 children must do a reasonable amount of work, they 



